查看当前磁盘信息：

[root@localhost ~]# df -h

文件系统          容量  已用  可用 已用%% 挂载点
/dev/mapper/VolGroup-lv_root
                      154G  7.9G  139G   6% /
tmpfs                 1.9G  100K  1.9G   1% /dev/shm
/dev/sda1             485M   69M  391M  15% /boot
/dev/mapper/VolGroup-lv_home

299G  984M  283G   1% /home

将VolGroup-lv_home缩小到20G，并将剩余的空间添加给VolGroup-lv_root

先卸载/home：

[root@localhost ~]# umount /home
[root@localhost ~]# e2fsck -f /dev/mapper/VolGroup-lv_home
e2fsck 1.41.12 (17-May-2010)
第一步: 检查inode,块,和大小
第二步: 检查目录结构
第3步: 检查目录连接性
Pass 4: Checking reference counts
第5步: 检查簇概要信息
/dev/mapper/VolGroup-lv_home: 21/19857408 files (0.0% non-contiguous), 1498180/79429632 blocks

注：e2fsck为检查磁盘正确性

[root@localhost ~]# resize2fs -p /dev/mapper/VolGroup-lv_home 20G

resize2fs 1.41.12 (17-May-2010)
Resizing the filesystem on /dev/mapper/VolGroup-lv_home to 5242880 (4k) blocks.
Begin pass 2 (max = 32778)
正在重定位块            XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Begin pass 3 (max = 2424)
正在扫描inode表          XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Begin pass 4 (max = 10)
正在更新inode引用       XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
The filesystem on /dev/mapper/VolGroup-lv_home is now 5242880 blocks long.

注：resize2fs 为重新设定磁盘大小，只是重新指定一下大小，并不对结果有影响，需要下面lvreduce的配合

[root@localhost ~]# mount /home
[
[root@localhost ~]# lvreduce -L 20G /dev/mapper/VolGroup-lv_home
  WARNING: Reducing active and open logical volume to 20.00 GiB
  THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce lv_home? [y/n]: y
  Reducing logical volume lv_home to 20.00 GiB
  Logical volume lv_home successfully resized

注：lvreduce -L 20G的意思为设置当前文件系统为20G，如果lvreduce -l 20G是指从当前文件系统上减少20G

[root@localhost ~]# df -h
文件系统          容量  已用  可用 已用%% 挂载点
/dev/mapper/VolGroup-lv_root
                      154G  7.9G  139G   6% /
tmpfs                 1.9G  100K  1.9G   1% /dev/shm
/dev/sda1             485M   69M  391M  15% /boot
/dev/mapper/VolGroup-lv_home
                       20G  962M   18G   6% /home（说明成功了）

[root@localhost ~]# vgdisplay
  --- Volume group ---
  VG Name               VolGroup
  System ID            
  Format                lvm2
  Metadata Areas        1
  Metadata Sequence No  7
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                3
  Open LV               3
  Max PV                0
  Cur PV                1
  Act PV                1
  VG Size               465.27 GiB
  PE Size               4.00 MiB
  Total PE              119109
  Alloc PE / Size       46660 / 182.27 GiB
  Free  PE / Size       72449 / 283.00 GiB
  VG UUID               gPA8XS-ZncK-mGQj-2Vn9-TFTQ-6yOU-6atjE9

注：vgdisplay为显示LVM卷组的元数据信息

[root@localhost ~]# lvextend -L +283G /dev/mapper/VolGroup-lv_root
  Extending logical volume lv_root to 439.39 GiB
  Logical volume lv_root successfully resized

注：lvextend -L +283G为在文件系统上增加238G

[root@localhost ~]# resize2fs -p /dev/mapper/VolGroup-lv_root
resize2fs 1.41.12 (17-May-2010)
Filesystem at /dev/mapper/VolGroup-lv_root is mounted on /; on-line resizing required
old desc_blocks = 10, new_desc_blocks = 28
Performing an on-line resize of /dev/mapper/VolGroup-lv_root to 115183616 (4k) blocks.
The filesystem on /dev/mapper/VolGroup-lv_root is now 115183616 blocks long.

检查一下调整的结果：

[root@localhost ~]# df -h
文件系统          容量  已用  可用 已用%% 挂载点
/dev/mapper/VolGroup-lv_root
                      433G  7.9G  403G   2% /
tmpfs                 1.9G  100K  1.9G   1% /dev/shm
/dev/sda1             485M   69M  391M  15% /boot
/dev/mapper/VolGroup-lv_home
                       20G  962M   18G   6% /home